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针对一台设计工况下输出功为1MW的CO2透平,在不同的超临界CO2循环模式下进行计算分析,发现带回热循环的性能大大优于简单循环,效率相对于简单循环提高了一倍多.并发现引入分流在一定分流比范围内能够提高系统的循环热效率,而当分流比过小时反而会使系统循环性能恶化.为了更好地利用有机朗肯循环(organic Ranking cycle,ORC)吸收CO2循环的余热,还对ORC的优化运行模式进行了研究,分析了过热度和热源出口温度的影响.最后,将CO2循环和ORC进行耦合,分析了不同分流比下联合循环和单一循环的性能差异,发现联合循环能在单一循环的基础上提升效率至少2％,并且当ORC窄点在耦合换热器预热段之间时,联合循环对系统性能有更大的提升.“,”Based on a CO2 turbine with an output power of 1MW under a design condition, calculations were made in different modes of supercritical CO2 cycle in this paper. The result shows that compared to the simple Brayton cycle (SBC), the performance of the regenerative Brayton cycle (RBC) is much better and the thermal efficiency is more than doubled. Furthermore, it is found that the introduction of the part-flow can improve the thermal efficiency of a CO2 cycle in a certain range of part-flow ratio, and the performance of the part-flow Brayton cycle (PFBC) will deteriorate if the part-flow ratio is too small. In order to use the Organic Rankine cycle (ORC) to absorb the waste heat released from the CO2 cycle, the optimized operation modes of the ORC were analyzed. For the superheated degree, the performance of ORCs will deteriorate when the superheated degree increased. This is mainly due to the decreasing of the expansion work. For heat source outlet temperature, there exists an optimum heat source outlet temperature for a fixed heat source inlet temperature, which made the expansion work reach the maximum value. Based on the conclusions above, we combined a CO2 cycle and an ORC as a combined cycle (CBC) to compare its performance with a PFBC under different part-flow ratios. The result shows that thermal efficiencies of CBCs are higher than PFBCs at least 2 percentage points, and when the pinch point is in the preheat section of the coupled heat exchanger (CHE), the performance of the combined cycle is even better.